1. Field of the Invention
The present invention relates to a head protecting air bag apparatus mounted in a vehicle. The air bag of the invention covers a portion of the inside of the vehicle when it unfolds and expands.
2. Description of Related Art
Conventional head protecting air bag apparatuses such as the ones disclosed in Japanese Patent Unexamined Publication No. Hei. 11-321532 are known. The air bags of this type is folded and housed in the upper edge side periphery of the vehicle""s inner side opening and extends over a front pillar portion/roof side rail portion of a vehicle body. A lid exists at the upper edge side of the vehicle""s inner side opening.
When this kind of air bag deploys, it opens the lid by pushing outward and covers the vehicle""s inner side opening. An attachment portion exists at the upper edge side of the air bag and allows the airbag to attach to the vehicle body. Further, the air bag is folded so that its lower edge side is next to its upper edge side. The attachment portion attaches to the vehicle body, so that the air bag is housed at the vehicle""s outer side of the lid (rear side of the lid).
The lid exists above a center pillar portion and a rear pillar portion in such a manner that it extends in the longitudinal direction of the vehicle. When the lid is pushed by the expanding air bag, it opens while its bottom is moved toward the inside of the vehicle. A pillar garnish for covering the inside of the vehicle is disposed at the pillar portion. The lower end of the lid is disposed at the vehicle""s outer side of the upper end of the pillar garnish.
Thus, when the expanding air bag pushes the lid the lid is hard to open at the position of the pillar portion because, at this position, the lower end of the lid gets over the upper end of the pillar garnish and is moved to the vehicle""s inner side, and the lid meets resistance. As a result, the air bag unfolds later at the location of the pillar portion than that at the other locations.
A restraining member exists at the upper position of the pillar portion. To prevent the unfolded and expanded air bag from intruding into the vehicle""s outer side of the pillar garnish. This restraining member is structured by a part with a substantially L-shaped section, including a vertical wall portion and a horizontal wall portion extending from the lower end of the vertical wall portion to the vehicle""s inner side. The vertical wall portion supports the vehicle""s outer side of the folded air bag. The horizontal wall portion supports the lower end side of the folded air bag.
However, if the restraining member is disposed over the pillar portion, there is a case where a part of the air bag disposed at the position of the restraining member is caught by the horizontal wall portion when the air bag unfolds and expands. In that case, the air bag unfolds at the location of the pillar portion later than at other locations.
An object of the present invention is to address the above problems. More specifically, an object of the present invention is to provide a head protecting air bag apparatus in which the air bag unfolds at the location of a pillar portion quickly.
Further, another object of the present invention is to provide a head protecting air bag apparatus in which even if a restraining member is located at the pillar portion, the air bag will quickly unfold at that location.
The object of the present invention is achieved by a head protecting air bag apparatus having the following structure. The head protecting air bag apparatus includes a lid and an air bag. The lid exists at the periphery of the upper edge side of the vehicle""s inner side opening and at the upper part of the pillar portion. The air bag is attached to the vehicle""s inner side and is housed on the vehicle""s outer side position of the lid in a folded state. When the gas flows into the airbag, it unfolds and expands by pushing and opening the lid. The air bag includes a lower edge, an upper edge, and an attachment portion at the upper edge for attachment to the vehicle body. The air bag is folded so that the lower edge approaches the upper edge, and the attachment portion is attached to the vehicle""s body so that it is housed at the vehicle""s outer side of the lid. A part of a lower end of the lid is disposed at a vehicle""s outer side of the upper end of a pillar garnish covering a vehicle""s inner side of the pillar portion.
In the head protecting air bag apparatus, the part of the air bag positioned at the lower end of the lid and at the vehicle""s outer side of the upper end of the pillar garnish, the lid pushing part, pushes more forcefully than other parts of the air bag in order to push the lid open. Thus, when the air bag unfolds and expands, the lower end of the lid easily gets over the upper end of the pillar garnish. As a result, the part of the air bag at the pillar portion quickly expands. Accordingly, the whole air bag smoothly unfolds and covers the vehicle""s inside opening.
The part of the air bag that pushes and opens the lid can be formed by twisting this part from the rest of the air bag so that this part unfolds and expands in the direction toward the lid.
When the air bag is in a non-expansion and flat unfolded state and is then folded in a bellows fold, in which it is folded substantially in a vertical direction from the lower edge side to the upper edge side, the lid pushing part of the air bag can be formed by twisting this part from the other part of the air bag so that a folding direction is directed toward the lid.
When the lid pushing part of the air bag is formed by twisting this part from the rest of the air bag, the desired structure is achieved. That is, a restraining member for preventing the air bag at the time of unfolding and expansion from intruding into the vehicle""s outer side of the pillar garnish exists at the upper position of the pillar portion. The restraining member has a guide surface so that the lid pushing part of the air bag is directed toward the lid when the air bag unfolds and expands. The lower end side of the guide surface is directed toward an upper side of a vehicle""s inner side parting portion between the lower end of the lid and the upper end of the pillar garnish. The air bag in the non-extension and flat unfolded state is folded in the bellows fold. The lid pushing part of the air bag is housed at the vehicle""s outer side of the lid while its folding direction is made parallel to the guide surface and supported by the guide surface.
In this case, when the air bag unfolds and expands, the lid pushing part unfolds along the guide surface of the restraining member toward the vehicle""s inner side, and can properly push and open the lid. Thus, the part of the air bag at the pillar portion unfolds more quickly. That is, the whole air bag unfolds more smoothly to cover the vehicle""s inner side opening.
The restraining member may be formed integrally with the vehicle body.
Besides, the restraining member may be formed into a flat plate shape existing substantially in the vertical direction, or may be provided with a part of a substantially L-shaped section as set forth below.
More specifically, the restraining member has the part of the substantially L-shaped section including a vertical wall portion and a horizontal wall portion extending from a lower end of the vertical wall portion toward the vehicle""s inner side. The vertical wall portion supports the vehicle""s outer side of the folded air bag. The upper surface side of the horizontal wall portion is a guide surface. The lower end side of the lid pushing part of the air bag is supported on the guide surface.
In the head protecting air bag apparatus, the part of the air bag existing at the position of the restraining member (the lid pushing part) is folded along the horizontal wall portion while the bellows fold state substantially in the vertical direction is twisted. Thus, when the expanding gas flows into the lid pushing part, the air bag""s volume is immediately expanded toward the vehicle""s inner side along the guide surface of the upper side of the horizontal wall portion. The lid pushing part pushes and opens the lid and projects toward the vehicle""s inner side without being caught by the horizontal wall portion of the restraining member. Of course, the part of the air bag other than the lid pushing part, folds substantially in the vertical direction and is folded in the bellows fold. Thus, when the air bag unfolds and expands, the other part of the air bag projects toward the lower side. Because of the force of the other part of the air bag toward the lower side, the lid pushing part also projects downward after projecting toward the vehicle""s inner side. As a result, the whole of the air bag smoothly covers the opening at the vehicle""s inner side.
When the lid pushing part of the airbag is formed without paying consideration to twisting, it may be structured by using a restraining member as follows. The restraining member exists at an upper position of the pillar portion, and when the air bag unfolds and expands prevents it from intruding into the vehicle""s outer side of the pillar garnish. The restraining member is provided with a part of a substantially L-shaped section including a vertical wall portion and a horizontal wall portion extending from a lower end of the vertical wall portion toward the vehicle""s inner side.
In a first case of the head protecting air bag apparatus where the lid pushing part is formed without paying consideration to twisting, the air bag in a non-expansion and flat unfolded state is folded in the bellows fold (in which it is folded substantially in the vertical direction from the lower edge side to the upper edge side). The vertical wall portion of the restraining member supports the vehicle""s outer side of the folded air bag. The horizontal wall portion of the restraining member supports the lower end side of the folded air bag, and is disposed so that an intersection angle to the lid is made an acute angle. The lid pushing part of the air bag is constructed by forming a part expanding at a narrow intersection part between the lid and the horizontal wall portion.
The above head protecting air bag apparatus operates as follows. The volume of the lid pushing part of the air bag, expands by the inflow of gas. The vehicle""s outer side end surface and the lower end surface of the expansion part are restrained by the vertical wall portion and the horizontal wall portion. Also in the upper side of the expansion part, upward large movement is restrained because the airbag is attached to the vehicle body by the attachment portion at the upper edge side of the air bag. As a result, the expansion part is moved along the horizontal wall portion to the lid side. The intersection angle between the horizontal wall portion and the lid is made acute. Thus, the expansion part intrudes into the narrow acute part between the horizontal wall portion and the lid when expanding, and further increases the pressure. As a result, the expansion part quickly pushes and opens the lid, and projects to the vehicle""s inner side. The lid itself is disposed substantially in the vertical direction. Since the intersection angle to the lid is acute, the horizontal wall portion exists not in a horizontal state but in a state slanted toward the vertical direction side. As a result, even if a part of the air bag is caught by the horizontal wall portion and is liable to remain, the air bag smoothly projects to the vehicle""s inner side in such a manner that it slides down the horizontal wall portion.
It is desirable that the intersection angle between the horizontal wall portion and the lid is in the range of 50xc2x0 to 80xc2x0. If the intersection angle exceeds 80xc2x0, a part of the air bag might be caught by the horizontal wall portion. If the intersection angle is less than 50xc2x0, a gap between the horizontal wall portion and the lid is too narrow, and the lid must be enlarged which is undesirable.
In a second case of the head protecting air bag apparatus where the lid pushing part of the air bag is formed without paying consideration to twisting, the air bag in the non-expansion and flat unfolded state is folded (in the bellows fold in which it is folded substantially in the vertical direction from the lower edge side to the upper edge side). The vertical wall portion of the restraining member supports the vehicle""s outer side of the folded air bag, and the horizontal wall portion of the restraining member supports the lower end side of the folded air bag. The lid pushing part is formed by disposing the lower edge tip end side of the air bag so as to cover the upper portion from the lower portion of the folded air bag through the vehicle""s inner side.
In the head protecting air bag apparatus described above, when the volume of the part of the air bag disposed at the position of the restraining member (the lid pushing part) is expanded by the inflow of the gas, the winding of the lower edge of the air bag (covering the upper portion from the lower portion of the folded air bag through the vehicle""s inner side) is loosened. Then the lower edge of the air bag is unfolded toward the vehicle""s inner side to push and open the lid, and projects to the vehicle""s inner side. Thereafter, the lid pushing part projects from the opening of the opened lid to the vehicle""s inner side. Then the lid pushing part smoothly projects to the vehicle""s inner side in such a manner that it is guided by the lower edge of the air bag projecting to the vehicle""s inner side, and the lower edge of the air bag is not caught by the horizontal wall portion.
In a third case of the head protecting air bag apparatus where the lid pushing part of the air bag is formed without paying consideration to twisting, a vertical wall portion of a restraining member supports the vehicle""s outer side of the folded air bag, and a horizontal wall portion supports the lower end side of the folded air bag. The lid pushing part is formed by folding the air bag so that a part near the vertical wall portion side is expanded at the beginning of the inflow of expanding gas.
For the head protecting air bag apparatus described above, when the expanding gas flows into the part of the air bag disposed at the position of the restraining member (the lid pushing part), the part of the air bag near the vertical wall portion side expands. Then, the part of the air bag at the lid side is pushed by the expansion, moves along the horizontal wall portion to push and open the lid, and projects to the vehicle""s inner side. Further, the part of the air bag near the vertical wall portion side, which is expanded from the beginning, also smoothly expands and projects to the vehicle""s inner side without being caught by the horizontal wall portion.
An example of the third head protecting air bag apparatus has an upstream side part and a downstream side part of the gas provided in the air bag. At the part of the air bag existing at the position of the restraining member (the lid pushing part), the upstream side part of the expanding gas exists at the vertical wall portion side of the restraining member, and the downstream side part of the expanding gas exists at the lid side.
In this case, the air bag may be folded substantially in the vertical direction. However, it may be folded as follows. A fold is provided substantially at an intermediate position in the vertical direction, and the air bag is folded in half from a flat unfolded state of a non-expansion state so that the lower edge side of the air bag is folded back to the vehicle""s inner side. Further, the air bag is folded in the bellows fold (in which it is folded substantially in the vertical direction from the lower edge side of the air bag folded in half to the upper edge side). In the lid pushing part of the air bag, the upstream side part exists at the upper edge side of the air bag in the non-expansion and flat unfolded state, and the downstream side part exists at the lower edge side of the air bag in the non-expansion and flat unfolded state.
For the head protecting air bag apparatus described above, when the expanding gas flows into the part of the air bag disposed at the position of the restraining member (the lid pushing part), the upstream side part of the gas at the vertical wall portion side expands. Then, the lower edge side part of the air bag is pushed by the upstream side part, pushes and opens the lid, and projects to the vehicle""s inner side. Then the upstream side and downstream side parts of the gas smoothly expand and project to the vehicle""s inner side without being caught by the horizontal wall portion.
In the case where the upstream side part of the gas exists at the vertical wall portion side of the restraining member, the downstream side part of the expanding gas is disposed at the lid side, and the lid pushing part of the air bag is formed, the following structure may be adopted. That is, in the lid pushing part, a projection portion projecting from the upstream side part is provided at the upper edge or the lower edge of the air bag. The projection portion is disposed at an end surface of the folded air bag at the vehicle""s outer side so that the projection portion faces the vertical wall portion of the restraining member.
In the above head protecting air bag apparatus, when the gas for expansion flows into the part of the air bag disposed at the position of the restraining member (the lid pushing part of the air bag), the upstream side part of the gas, together with the projection portion, expands. The projection portion is restrained by the vertical wall portion. Thus, a part other than the projection portion is pushed by the projection portion and is moved along the horizontal wall portion, so that it pushes and opens the lid and projects to the vehicle""s inner side. As a result, both the upstream side and downstream side parts of the gas for expansion are smoothly expanded and project to the vehicle""s inner side without being caught by the horizontal wall portion.
The following structure may be adopted as another example of the third head protecting air bag apparatus. An expansion portion into which the expanding gas can flow, and a non-expansion portion into which the expanding gas can not flow are provided in the lid pushing part of the air bag. At the edge of the expansion portion in the vertical direction, the periphery is cut out to form a cut piece portion which can be bent to the vehicle""s outer side. The cut piece portion is disposed at the end surface of the folded air bag at the vehicle""s outer side so that it faces the vertical wall portion of the restraining member.
In the head protecting air bag apparatus described above, when the expanding gas flows into the air bag, in the part of the air bag disposed at the position of the restraining member (the lid pushing part), the expansion portion, together with the cut piece portion, expands. The cut piece portion is restrained by the vertical wall portion. Thus, the cut piece portion pushes a part other than the cut piece portion and moves it along the horizontal wall portion so that it pushes and opens the lid and projects to the vehicle""s inner side. As a result, the cut piece portion near the vertical wall portion side, which expands from the beginning, smoothly expands and projects to the vehicle""s inner side without being caught by the horizontal wall portion.
A fourth head protecting air bag apparatus exists where the lid pushing part of the airbag is formed without paying consideration to twisting, the vertical wall portion supports the vehicle""s outer side of the folded air bag, and the horizontal wall portion supports the lower end of the folded air bag. The air bag in the non-extension and flat unfolded state and is folded in the bellows fold (in which it is folded substantially in the vertical direction from the lower edge side to the upper edge side). In the lid pushing part, an upper edge side flow path which exists at the upper edge of the air bag and in which the expanding gas can flow, and a lower edge flow path which exists at the lower edge of the air bag and in which the expanding gas can flow, are provided. The flow rate of the expanding gas in the lower edge side flow path is set larger than the flow rate of the gas for expansion in the upper edge side flow path.
In the fourth head protecting air bag apparatus described above, when the expanding gas flows into the air bag, in the part of the air bag disposed at the position of the restraining member (the lid pushing part), the volume of the lower edge side flow path at the horizontal wall portion side expands. Then the side of the upper edge side flow path is pushed up in the direction orthogonal to the horizontal wall portion. However, since the attachment portion of the upper edge side of the air bag is attached to the vehicle body, and the volume of the upstream side flow path is slightly expanded, large movement to the upside is restrained. Accordingly, the part of the air bag disposed at the position of the restraining member (the lid pushing part) is guided to the lid side where the vertical wall portion is not disposed, pushes and opens the lid, and projects to the vehicle""s inner side. As a result, in the part having the intensified force to push and open the lid, both the upper edge side and lower edge side parts are smoothly expanded and project to the vehicle""s inner side without being caught by the horizontal wall portion.
In a fifth case of the head protecting air bag apparatus where the lid pushing part of the air bag is formed without paying consideration to twisting, the vertical wall portion supports the vehicle""s outer side of the folded air bag, and the horizontal wall portion supports the lower end side of the folded air bag. The lid pushing part is provided with a flexible wrapping sheet covering the folded air bag. An upper end of the wrapping sheet is fixed to the upper edge of the air bag. A lower end of the wrapping sheet is wound around the vehicle""s inner side of the folded air bag and the lower end and is brought into contact with the horizontal wall portion of the restraining member. Further, the lower end of the wrapping sheet is inserted between the folds of the folded air bag at the vehicle""s outer side and is held between the folds to be disposed. The frictional resistance of a front surface of the wrapping sheet brought into contact with the horizontal wall portion is made lower than the frictional resistance of a back surface brought into contact with the air bag.
In the fifth head protecting air bag described above, when the volume of the part of the air bag disposed at the position of the restraining member (the lid pushing part) expands by the inflow of the expanding gas, it is pushed up in the direction orthogonal to the horizontal wall portion. However, the attachment portion of the upper edge side of the air bag is attached to the vehicle body, and large movement to the upside is restrained. Thus, the lid pushing part is guided to the lid side where the vertical wall portion is not disposed. The frictional resistance of the front surface of the wrapping sheet brought into contact with the horizontal wall portion is made lower than that of the back surface brought into contact with the air bag. Thus, while the state where the lower end of the wrapping sheet is held between the folds of the folded air bag at the vehicle""s outer side is maintained, the lid pushing part slides on the horizontal wall portion and is guided to the lid side where the vertical wall portion is not disposed. Then the lid pushing part pushes and opens the lid, and projects to the vehicle""s inner side. Further, the lower end of the wrapping sheet drops out of the folds of the air bag, and the winding of the wrapping sheet is loosened. As a result, the lid pushing part smoothly expands and projects to the vehicle""s inner side without being caught by the horizontal wall portion.